Contact lenses have been used commercially to improve vision since the 1950s. Contact lenses are currently available in a range of materials and millions of people wear contact lenses as their primary mode of optical correction.
Spectacle and contact lenses which block substantial amounts (greater than 80%, and often greater than 90%) have been disclosed. Sunglasses, for example, block substantial quantities of UV and visible light. UV absorbing contact lenses also substantially block UV light, but provide nearly 100% transmission in the visible light range so the contact lenses can be worn in all lighting conditions.
Contact lenses which selectively block specific wavelengths of light have been disclosed for a variety of purposes, including blocking blue wavelengths of light to prevent or retard cataract formation. Contact lenses tinted to improve handling or provide a cosmetic effect have also been disclosed. Photochromic contact lenses have also been disclosed to be useful for reducing glare and light intensity in bright sunlight.
In the past decade computers have become ubiquitous in offices, schools and homes. Extended periods of computer use can cause eye strain, and, in contact lens wearers additional discomfort and dryness as people tend to blink less when reading and working on the computer. Thus, there remains a need for contact lenses which remain comfortable during long periods of wear, especially while working indoors under artificial lights and/or on computers.